The aforesaid patents disclose a sponge rubber collar having a radial slit therein with overlapping edges for adjustment to necks of different size. Other types of such collars are known, such as the elastic spiral twist collar and the annular sponge rubber collar which is stretched to allow the head of a patient to pass therethrough and then relax to fit snugly around the neck.
All of these known collars have inherent disadvantages, especially for infants. They are essentially flat in use, i.e. the body of the collar remains in a plane at right angles to the neck and closes as tightly on delicate structures of the anterior neck and anterior lateral neck, such as the jugular vein, carotid arteries and trachea, as it does on the posterior neck, i.e. the back of the neck, which has no such superficial delicate structures. Such collars sometimes injure the skin and subcutaneous tissues as well as exert undesirable undue pressure on the jugular vein, carotid arteries, trachea and other delicate structures in the anterior neck and anterior lateral neck. The spiral twist plastic collar has the additional disadvantage of causing a tightening of the collar about the entire neck when pressure is increased in the head or body compartment, producing a highly undesirable tourniquet effect on the neck of the patient.